If 98 out of 200 individuals in a population express the recessive phenotype, what percent of the population would you predict would be heterozygotes?
49%
42%
90%
70%
As we have already studied in Hardy Weinberg Equilibrium -
According to Hardy-Weinberg equilibrium,
(p + q) 2 = 1 or p2 + q2 + 2pq = 1
According to this question,
q2 (aa) = 98
Frequency of the allele ‘a’ would be 98/200 = 0.49
Therefore, √0.49 = 0.7 = q
Hence, 1 - q = p
1 - 0.7 = 0.3 Therefore, p = 0.3
Now we have both p = 0.3 and q = 0.7
Frequency of the heterozygous genotype = 2pq
Thus, = 2 x 0.3 x0.7
= 0.42
Hence, the population of the heterozygotes would be 42% and the correct option is (b).